KR102314169B1 - Apparatus for chemosensing and Method for measuring apparatus - Google Patents

Abstract

Disclosed is a chemical detection apparatus capable of receiving a plurality of signals as one output signal through circuit design for a multi-detection technique. The chemical detection device may include a substrate, a transducer disposed on the upper surface of the substrate, and a reflector formed at an end of the transducer.

Description

Chemical detection apparatus and its measuring method {Apparatus for chemosensing and Method for measuring apparatus}

The present invention relates to a chemical sensing device, and more particularly, a single surface acoustic wave sensor to which a miniaturized multi-array technique of a SAW (Surface Acoustic Wave) sensor-based chemical detection sensor is applied, a chemical detection device having the same, and a control method thereof will be.

Surface Acoustic Wave (SAW) is a wave in which the energy of the wave is concentrated on the surface layer and the entire surface layer vibrates and propagates. In both cases, the vibration direction is perpendicular to the wave travel direction, but the Rayleigh wave vibrates in the vertical direction and the Love wave vibrates in the horizontal direction.

SAW is widely used as a temperature sensor, pressure sensor, communication filter, etc. In general, piezoelectric materials such as quartz, lithium niobate, and lithium tantalate are used to produce a piezoelectric effect. is made

The piezoelectric effect refers to the formation of a voltage due to the internal polarization of a material due to deformation due to pressure, and vice versa. As an example of a technology using SAW using such a material, when a voltage is applied through an electrode, electrical energy is converted into mechanical energy in an input IDT (Interdigital Transducer) to generate SAW, and this is outputted as an electrical signal in the output IDT 2 There is a -port method.

SAW can be applied as a chemical detection sensor, and its principle is as follows. When the sensitive film deposited on the delay line between the input and output IDTs adsorbs the target material, the resonance frequency change and the phase change occur due to the mass loading effect. It is possible to know the presence and concentration of the target substance.

At this time, since there are factors affecting the resonant frequency of the SAW sensor, such as temperature, humidity, and pressure, there is a disadvantage that the sensor characteristics change when the surrounding environmental conditions change.

In addition, since only one target substance can be detected with one SAW device, a plurality of SAW sensors and a measuring device for measuring each of the sensors are required to detect a plurality of substances. In other words, there is a problem in that only one chemical substance can be detected using a single SAW sensor, or there is no selectivity for different target substances.

A suitable measuring device includes a network analyzer, but in general, it is expensive, heavy, and bulky, so it is almost impossible to use it as a portable device.

1. Korea Patent No. 10-1847389 (Registration Date 2018.04.04)

The present invention has been proposed to solve the problem according to the above background art, and it is an object of the present invention to provide a chemical detection apparatus capable of receiving a plurality of signals as one output signal through circuit design for a multi-detection technique, and a control method thereof There is this.

Another object of the present invention is to provide a chemical detection device to which a small multi-array technique is applied and a control method thereof, which can be used without a separate measuring device.

Another object of the present invention is to provide a chemical detection device capable of compensating for a frequency change due to an external environment through a circuit design technique using a mixer, and a control method thereof.

Another object of the present invention is to provide a chemical detection apparatus capable of mounting a plurality of SAW sensors in one circuit and a control method thereof.

The present invention provides a chemical detection apparatus capable of receiving a plurality of signals as one output signal through a circuit design for a multi-detection technique in order to achieve the above object.

The chemical detection device,

Board;

a transducer disposed on the upper surface of the substrate; and

and a reflector formed at the distal end of the transducer.

In this case, the transducers are composed of two, and the two transducers are positioned symmetrically with respect to the sensing film deposited on the center of the upper surface of the substrate.

In addition, the sensing film is characterized in that any one of a metal oxide layer (metal oxide layer), a monomolecular or polymer-based polymer film (polymer film), carbon nanotube (carbon nanotube), and cellulose.

In addition, the material of the substrate is characterized in that it is a piezoelectric material that can be converted between electrical energy and mechanical energy.

In addition, the piezoelectric material is characterized in that any one of _{quartz, GaAs, ZnO, LiTaO 3} , LiNbO ₃ , and PbZrO _{3 .}

In addition, the reflector is characterized in that it is connected to the measuring device through a pin formed on the lower surface of the substrate.

On the other hand, another embodiment of the present invention is a reference oscillator having a reference sensor without a sensing film; n or more oscillators each having a single surface acoustic wave sensor with the sensing film; n mixers for outputting n summation signals generated by the sum of the first signal generated from the reference oscillator and the n second signals generated from the n number of oscillators; Transmitting the n summation signals to a single output line It provides a chemical detection device comprising; a multiplexer.

In this case, the chemical detection apparatus may include a comparator that compares the n sum signals with a preset reference value and generates a comparison result signal when a predetermined frequency change level preset for each target material is exceeded.

Also, the chemical detection device may include a microcontroller unit configured to generate alarm information according to the comparison result signal.

In addition, the chemical detection device, a display for outputting the alarm information; characterized in that it comprises a.

In addition, the alarm information is characterized in that a combination of graphics, text, voice, and vibration.

In addition, the n sum signals are generated by measuring a difference in resonance frequency between the first signal and the n second signals in order to remove the environmental variable.

In this case, the environmental variable is characterized in that the environmental variable is at least one of ambient temperature, humidity, and pressure.

In addition, the first signal is characterized in that it is generated before the n second signals.

In addition, the sensing film is characterized in that each of the n oscillators are coated with a different sensing material.

On the other hand, another embodiment of the present invention comprises the steps of: (a) generating a first signal by a reference oscillator having a reference sensor; (b) generating a second signal by n oscillators each having a single surface acoustic wave sensor with a sensing film; and (c) outputting, by n mixers, n sum signals generated by adding the first signal and the n second signals, respectively; and (d) transmitting, by a multiplexer, the n summed signals to a single output line.

According to the present invention, a plurality of Surface Acoustic Wave (SAW) sensors can be mounted and used at the same time.

In addition, as another effect of the present invention, it is possible to measure multiple target substances with high selectivity by simultaneously mounting and using a plurality of SAW sensors.

In addition, as another effect of the present invention, it is possible to minimize the influence of the surrounding environment such as temperature.

In addition, as another effect of the present invention, there is no need for additional correction according to season or weather.

In addition, as another effect of the present invention, since the economical efficiency is excellent compared to other devices, the possibility of its utility in the military and industry is large.

1 is a plan view illustrating a conceptual diagram of a single surface acoustic wave sensor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the II axis of the single surface acoustic wave sensor shown in FIG. 1 .
3 is a block diagram of a chemical detection device to which the single surface acoustic wave sensor shown in FIGS. 1 to 2 is applied as an array.
4 is a flowchart of an algorithm according to an embodiment of the present invention.
5 is a view showing the appearance of an analog board for processing an analog signal in a circuit according to an embodiment of the present invention.
6 is a view showing the appearance of a digital board for digital signal processing after an analog-digital converter (ADC) according to an embodiment of the present invention.
7 is an example of a substrate in which the components shown in FIGS. 1 to 6 are combined.
8 is an example of an external perspective view of a chemical detection device in which the components shown in FIGS. 1 to 7 are combined.
9 is a screen example of a test device for testing the performance of the chemical detection device according to an embodiment of the present invention.
FIG. 10 is an enlarged graph of the screen example shown in FIG. 9 .
11 is an example of a product to which chemical detection detection according to an embodiment of the present invention is applied.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals are used for like elements. The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. shouldn't

Hereinafter, a chemical detection apparatus and a control method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan view showing a conceptual diagram of a single surface acoustic wave sensor 100 according to an embodiment of the present invention. Referring to FIG. 1 , the single surface acoustic wave sensor 100 is a single SAW (Surface Acoustic Wave) sensor. The substrate 110, the sensing film 120 deposited on the center of the upper surface of the substrate 110, and the sensing film 120 It may be configured to include a transducer 130 disposed on both sides of the reference, a reflector 140 formed at the end of the transducer 130, and the like.

The substrate 110 is manufactured using a piezoelectric material capable of converting both electrical energy and mechanical energy. As a material of the substrate 110 , in order to dramatically reduce frequency fluctuations caused by ambient temperature, quartz having a temperature-stable frequency characteristic may be used. In addition to the piezoelectric material, GaAs, ZnO, LiTaO ₃ , LiNbO ₃ , PbZrO _{3 ,} etc. may be used.

The transducer 130 is an IDT (Interdigital Transducer), and a metal electrode pattern is disposed on the surface of the substrate 110 . Accordingly, it performs a function of converting an electrical signal into a surface acoustic wave. In addition, the resonant frequency of the single surface acoustic wave sensor 100 can be adjusted through the pattern design of the IDT (Interdigital Transducer). In the case of ceramic materials or quartz, which are generally used as piezoelectric materials, since they do not have electrical conductivity, they can be used by depositing a metal electrode layer on a substrate.

A space between the two converters 130 is called a delay line. The sensing film 120 is positioned on this delay line.

The types of the sensing film 120 deposited on the SAW sensor are different from each other, and there are various types of sensing films having sensing performance for target materials, such as a metal oxide layer or a polymer film, carbon nanotube, and cellulose. material may be used. That is, any material having a property of reversibly adsorbing/desorbing a target substance can be used.

The principle of target material detection of the SAW sensor is as follows. When power is applied to the electrode of the input-side transducer 130 , the fingers 131 vibrate due to the piezoelectric effect, and the vibration energy is transmitted to the output-side transducer 130 through the sensing film 120 .

In general, a network analyzer, a spectrum analyzer, or the like may be used to measure this signal. Using these measuring devices, s-parameters, phases, etc. can be measured for each frequency, and in this case, the transmission S ₂₁ shows the intensity of the output signal versus the input.

When the sensing film 120 deposited on the delay line adsorbs the target material through a physical/chemical process, the mass increases and the resonant frequency of the SAW sensor is adjusted according to the mass-loading effect. This is a measure of material detection, and the degree of frequency shift varies according to the target material concentration and the characteristics of the sensing film.

The reflector 140 functions to reflect the surface acoustic wave formed by the transducer 130 .

FIG. 2 is a cross-sectional view taken along the I-I axis of the single surface acoustic wave sensor 100 shown in FIG. 1 . Referring to FIG. 2 , the connection between the measuring device (not shown) and the reflector 140 is made through a pin 250 . The SAW sensor is a 2-port resonator type and has a reflector 140, but it is also applicable to 1-port and transversal types.

In general, in the case of a SAW sensor, the propagation speed of the surface wave varies depending on the medium in which the wave propagates and the state of the medium opposite the interface. Environmental variables of various conditions such as ambient temperature, humidity, and pressure affect this. Since this causes a change in the resonant frequency in units of kHz, it must be removed for more accurate detection.

Therefore, it is necessary to reduce these environment variables. Since each single surface acoustic wave sensor has environmental variables, it is detected based on one single surface acoustic wave sensor without a detection film. Variables can be removed. A concept showing this is shown in FIG. 3 .

3 is a block diagram of a chemical detection device to which the single surface acoustic wave sensor shown in FIGS. 1 to 2 is applied as an array. In particular, FIG. 3 is a conceptual diagram schematically illustrating an algorithm of error correction due to a sensor multi-array and/or environmental variables, which are important concepts.

Referring to FIG. 3 , a reference oscillator 311 having a reference sensor 301 without a detection film 120 , and first to n-th oscillators 310 having a single surface acoustic wave sensor 100 with a detection film 120 . -1 to 310-n), first to nth mixers 320-1 to 320-n, first to nth low-pass filters 330-1 to 330-n, multiplexer 340, final low-pass It may be configured to include a filter 350 , a buffer 360 , a comparator 370 , a microcontroller unit 380 , and a display 390 .

A low pass filter (LPF) 302 , a radio frequency (RF) amplifier 303 , and the like may be configured in the reference oscillator 311 and the first to nth oscillators 310-1 to 310-n. Accordingly, the reference oscillator 311 low-pass filters the signal generated from the reference sensor 301 and amplifies and outputs the signal, and the first to nth oscillators 310-1 to 310-n are also single surface acoustic wave sensors. It functions to low-pass filter the signal generated from (100), amplify it, and output it.

The first to nth mixers 320-1 to 320-n are devices that calculate and output the sum or difference of respective resonant frequencies when two signals are input. Accordingly, the difference between the resonant frequencies of the reference signal generated from the reference oscillator 311 and the output signals output from the first to nth oscillators 310-1 to 310-n is calculated and output.

In other words, the difference between the resonance frequencies of the single surface acoustic wave sensor 100 of the reference sensor 301 and the first oscillator 310-1 becomes the sum signal #1, and similarly, the second oscillator 310-2 and the third oscillator The sum signals #2 and #3 are also output at (310-3). Signals #1, #2, #3... output in this way pass through a multiplexer 340 and are transmitted through a single output line.

A final signal from which high-frequency noise is removed is generated by disposing first to n-th low-pass filters (LPF) (330-1 to 330-n) at the rear end of each of the mixers 320-1 to 320-n. . In addition, a final low-pass filter 350 is also disposed at the front end of the multiplexer 340 to remove high-frequency noise.

The buffer 360 performs a function of buffering final signals from which high-frequency noise has been removed. In other words, since a signal is continuously transmitted from the multiplexer 340, a transmission speed difference occurs between an input speed and an output speed, and thus performs a function of resolving the speed difference.

The comparator 370 compares a preset reference value with the final signals and transmits a comparison result signal to the microcontroller unit 380 when a preset frequency change level is exceeded for each target material.

The microcontroller unit 380 receives the comparison result signal from the comparator 370 , generates alarm information, and outputs the alarm information through the display 390 . To this end, the microcontroller unit 380 may include a microprocessor, a memory, a program, and the like. The alarm information may consist of a combination of graphics, text, vibration, and sound.

The memory is a flash memory type, a hard disk type, a multimedia card micro type, and a card type memory (for example, SD (Secure Digital) or XD (eXtreme Digital)) memory, etc.), RAM (Random Access Memory, RAM), SRAM (Static Random Access Memory), ROM (Read Only Memory, ROM), EEPROM (Electrically Erasable Programmable Read Only Memory), PROM (Programmable Read Only Memory), magnetic memory , a magnetic disk, and an optical disk may include at least one type of storage medium.

The display 390 may be a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display panel (PDP), an organic LED (OLED) display, a touch screen, a cathode ray tube (CRT), a flexible display, or the like. have.

A sound system (not shown) may be configured to output sound. Of course, a sound system may be configured on the display. Of course, the vibration element can be configured for vibration. Also, a sound is a concept that may include a voice, a buzzer, and the like.

4 is a flowchart of an algorithm according to an embodiment of the present invention. Referring to FIG. 4 , a signal of a reference sensor 301 on which a sensing film is not deposited, which is a reference among a plurality of sensors ( 110 and 301 in FIG. 3 ) is read (step S410 ). Since the reference sensor 301 is hardly affected by the type of the surrounding gas, it is used as a reference value for correcting the resonance frequency change due to the surrounding environment such as temperature, humidity, and pressure.

Thereafter, signals of the single surface acoustic wave sensor 100 are generated (step S420). That is, the resonance frequency difference with the reference sensor 301 is calculated by reading the signals of the n single surface acoustic wave sensors 100 coated with different sensing materials (step S430). In other words, a different material may be coated on the surface of each sensing film 120 . The sensing film is characterized in that it is any one of a metal oxide layer such as ZnO and SnO, a polymer film containing silsesquioxane, thiourea, etc., a carbon nanotube, and cellulose. Such a sensing film has characteristics of improving sensitivity by selectively reacting to various chemicals.

Thereafter, it is determined whether it is the last single surface acoustic wave sensor 100 (step S440). If it is not the last single surface acoustic wave sensor 100 in step S440, steps S420 to S440 proceed again.

On the other hand, if it is determined in step S440 as the last single surface acoustic wave sensor 100, the microcontroller unit 380 outputs a frequency difference value to the display 390 (step S450).

Thereafter, when the resonance frequency difference in the at least one single surface acoustic wave sensor 100 exceeds a predetermined frequency change level preset for each target material, alarm information is provided to the user (steps S460 and S470).

5 is a view showing an appearance of an analog board 500 for processing an analog signal in a circuit according to an embodiment of the present invention. Referring to (a) and (b) shown in FIG. 5 , the analog board 500 includes mixers 531 , 532 , 533 , a power splitter 510 , and peripheral elements.

Signals after the mixers 531 , 532 , and 533 are passed through pin 520 to the next stage. In an embodiment of the present invention, the analog signal processing unit and the digital signal processing unit are divided into a two-board form, but this is not limited by the number and shape of the boards. In FIG. 5, four single surface acoustic wave sensors 100 are mounted and used (b).

6 is a view showing the appearance of a digital board for digital signal processing after an analog-digital converter (ADC) according to an embodiment of the present invention. Referring to FIG. 6 , a signal output from the previous stage is received through the pin connect 620 . Thereafter, the signal output to the small display 390 can be directly viewed through the interface circuit.

7 is an example of a substrate 710 in which the components shown in FIGS. 1 to 6 are combined. Referring to (a), (b) and (c) of FIG. 7 , a single surface acoustic wave sensor 100 , an analog board 500 , and a digital board 600 are illustrated.

8 is an example of an external perspective view of a chemical detection device in which the components shown in FIGS. 1 to 7 are combined. That is, FIG. 8 shows a state in which the components are combined in the housing 800 . The summation signals #1, #2, and #3 can be visually confirmed through the display 390 . In FIG. 8 , a liquid crystal display (LCD) panel is used as the display 390 .

9 is a screen example of a test device for testing the performance of the chemical detection device according to an embodiment of the present invention, and FIG. 10 is an enlarged graph of the screen example shown in FIG. 9 . Referring to FIGS. 9 and 10 , it is an experiment result for DMMP (dimethyl methyl phosphonate) gas using three different polymer sensing layers. 100, 75, 50, 25, and 13 ppm of DMMP gas was used, and the resonance frequency shifts tended to be different for each sensing film (1010, 1020, 1030).

11 is an example of a product to which a chemical detection device is applied. Referring to FIG. 11 , it is driven by a small battery, and an LCD panel and a charging circuit are included in the entire circuit. As shown in FIGS. 9 and 10 , it refers to the development of a system capable of simultaneous detection of three types, and in one embodiment of the present invention, a device as shown in FIG. 11 can be manufactured as an example of the application.

Since the resonant frequency of the single surface acoustic wave sensor 100 coated with each sensing film 120 changes according to the concentration of the A, B, and C materials, it is converted into visual data and displayed and an alarm sounds. It can act as an unnecessary chemical sensor.

100: single surface acoustic wave sensor 110: substrate
120: sensing film 130: transducer
140: reflector 250: pin
300: chemical detection device
301: Reference sensor 302: LPF: Low Pass Filter
303: Radio Frequency Amplifier
311: reference oscillator
310-1 to 310-n: first to nth oscillators
340: multiplexer
370: comparator
380: microcontroller unit
390: display

Claims (16)

delete delete delete delete delete delete a reference oscillator 311 having a reference sensor 311;
n oscillators 310-1 to 310-n each having a single surface acoustic wave sensor 100 with a sensing film 120;
The n sum signals generated by the sum of the first signal generated from the reference oscillator 311 and the n second signals generated from the n oscillators 310-1 to 310-n, respectively, are outputted. n mixers (320-1 to 320-n);
including; a multiplexer 340 for transmitting the n summed signals to a single output line;
The single surface acoustic wave sensor 100,
substrate 110;
a transducer 130 disposed on the upper surface of the substrate 110; and
It includes; a reflector 140 formed at the end of the converter 130.
The transducer 130 consists of two, and the two transducers 130 are positioned symmetrically with respect to the sensing film 120 deposited on the center of the upper surface of the substrate 110 . .
8. The method of claim 7,
and a comparator (370) that compares the n sum signals with a preset reference value and generates a comparison result signal when a predetermined frequency change level preset for each target substance is exceeded.
9. The method of claim 8,
and a microcontroller unit (380) for generating alarm information according to the comparison result signal.
10. The method of claim 9,
A chemical detection device comprising a; a display (390) for outputting the alarm information.
10. The method of claim 9,
The alarm information is a chemical detection device, characterized in that a combination of graphics, text, voice, and vibration.
8. The method of claim 7,
The n summation signals are generated by measuring the respective resonance frequency differences between the first signal and the n second signals in order to remove an environmental variable.
13. The method of claim 12,
The environmental variable is a chemical detection device, characterized in that at least one of ambient temperature, humidity, and pressure.
8. The method of claim 7,
wherein the first signal is generated before the n second signals.
8. The method of claim 7,
The detection film 120 is a chemical detection device, characterized in that each of the n oscillators (310-1 to 310-n) are coated with a different detection material.
(a) a reference oscillator 311 having a reference sensor 311 generating a first signal;
(b) generating the n second signals by n oscillators 310-1 to 310-n each having a single surface acoustic wave sensor 100 with a sensing film 120; and
(c) outputting, by the n mixers 320-1 to 320-n, the n sum signals generated by adding the first signal and the n second signals, respectively; and
(d) transmitting, by the multiplexer 340, the n summed signals to a single output line;
A chemical detection method comprising a.

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